1. Field of the Invention
The present invention relates to a battery unit for use in devices and appliances such as portable telephones, which battery unit is provided with a housing, with one or more cells which generate energy, with output contacts for connecting the cells to an appliance, and with external walls comprising an upper wall, a lower wall and side walls. Such a battery unit is known, for example, from its use in various types of portable telephones.
The present invention further relates to a portable battery-operated device including such a battery unit.
2. Description of the Related Art
Manufacturers continuously strive to make battery-operated devices of various kinds, in particular portable devices, as light and as small as possible. It is accordingly essential for the battery used to have the greatest possible capacity accompanied by the smallest possible dimensions and the smallest possible mass. Reference is made in this connection to European patent application 96402738.7 filed earlier by applicant but not yet published, which is deemed to be incorporated in its entirety in the present application by reference. The portable telephone described in said earlier application is provided with a flat, substantially rectangular battery unit which is provided adjacent its long sides with ridges and/or grooves for guiding the battery unit into associated portions of the housing of the portable telephone. The battery unit is provided with an external envelope which at the same time serves as an external part of the telephone. The external envelope is substantially entirely closed and is provided with a number of output contacts at the area of one of the external walls, which contacts achieve an electrical connection with corresponding contact elements of the telephone after the unit has been inserted into the portable telephone.